Field of the Invention
The present invention relates to an input interface, which is used with a pointing object such as a finger or a stylus.
Description of the Related Art
Devices that enable users to operate, with a pointing object, a user interface (UI) component projected on a predetermined projection surface such as a wall surface or a table surface by a projector are now increasingly used. Further, devices that display a UI component, for example, a virtual to operate the UI component displayed in a superimposed manner using a head mounted display is increasingly used as well. Such devices detect a tip of the pointing object, for example, a fingertip, from an image (hereinafter referred to as “depth image”) containing depth information (distance information), which is picked up with an image pickup device such as a visible light stereo camera, an infrared stereo camera, or a depth image sensor. An operation with a pointing object is detected based on the movement or position of the detected tip of the pointing object in a three-dimensional space.
In order to detect an operation with a pointing object on a UI component, the position of the tip of the pointing object in the three-dimensional space needs to be detected or estimated accurately. However, display of the tip of the pointing object imaged by the image pickup device changes depending on the position or angle of the pointing object with respect to the image pickup device, and thus it is difficult to detect the position of the tip of the pointing object in the three-dimensional space accurately. In U.S. Pat. No. 9,342,189 B2, there is proposed an information processing device configured to detect the three-dimensional position of the fingertip accurately using a luminance value of the reflected infrared light that changes in accordance with the position or horizontal angle of the fingertip.
In order to detect the position of the pointing object in the three-dimensional space accurately based on the depth image (range image), adverse effects of deviations and noises of the depth information contained in the depth image need to be suppressed. However, the information processing device proposed in U.S. Pat. No. 9,342,189 B2 does not consider detecting the position of the tip of the pointing object in the three-dimensional space based on the depth image picked up by one depth image sensor. The present invention has been made in view of the above-mentioned problem, and therefore has an object to provide an information processing device capable of detecting the position of a pointing object in a three-dimensional space accurately using a depth image.